TWI744361B - Thermal conductive polysiloxane composition - Google Patents

Abstract

The present invention provides a thermal conductive polysiloxane composition which has excellent workability and high thermal conductivity due to low viscosity.

The thermal conductive polysiloxane composition of the present invention is a thermal conductive polysiloxane composition containing (A) thermal conductive filler, and (B) at least one selected from the group of alkoxysilyl-containing compounds and dimethylpolysiloxane, and (A) component comprises two or more types of thermal conductive fillers with different average particle sizes, and at least 20 mass% of vagiform aluminum nitride particles having an average particle size as 30μm or more and 150μm or less, based on all (A) components.

Description

Thermally conductive polysiloxane composition

The present invention relates to a thermally conductive polysiloxane composition.

Electronic equipment has been increasing in size and speed over the years, and in response to this, the demand for heat dissipation materials for thermal countermeasures has also increased. Most of the heat dissipation materials use silicone resin compositions. However, silicone resin alone cannot improve thermal conductivity, so thermal conductivity fillers must be used together. As thermally conductive fillers, it is known to add silicon oxide powder, aluminum oxide, boron nitride, aluminum nitride, magnesium oxide, etc. as representative to make the silicone resin as a binder (binder) more thermally conductive. Material (Patent Document 1).

In order to improve the thermal conductivity of the silicone resin composition, the thermal conductivity agent must be highly filled. However, only one type of thermally conductive filler has a limit even if it is highly filled, so it is necessary to use multiple thermally conductive fillers with different particle diameters. Agent. For example, for the purpose of having good workability and excellent heat dissipation performance, a thermally conductive silicone grease composition is disclosed, which contains heat conduction with an average particle size of 12 to 100 μm (preferably 15 to 30 μm). A filler and a thermally conductive filler having an average particle diameter of 0.1 to 10 μm (preferably 0.3 to 5 μm) (Patent Document 2). Furthermore, it is also disclosed that there is an addition reaction type thermally conductive polysiloxane composition, which is composed of amorphous alumina with an average particle size of 10 to 30 μm, spherical alumina with an average particle size of 30 to 85 μm, and an average particle size of 0.1 to An insulating inorganic filler of 6 μm is blended in a specific ratio (Patent Document 3).

[Prior Technical Literature] [Patent Literature]

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-003831.

Patent Document 2: Japanese Patent Application Laid-Open No. 2009-096961.

Patent Document 3: JP 2013-147600 A.

However, in the silicone compositions of Patent Documents 2 and 3, when a thermally conductive filler is to be highly filled, the viscosity of the composition increases and the workability deteriorates. The polysiloxane compositions of Patent Documents 2 and 3, which are highly filled with thermally conductive fillers in a range where workability does not decrease, still have insufficient thermal conductivity.

Furthermore, the inventors of the present invention focused on aluminum nitride with high thermal conductivity as a thermally conductive filler, and after careful examination of the high-filling of spherical aluminum nitride, they found that a highly thermally conductive filler can be obtained. Composition. However, when this composition system is to be highly filled with a thermally conductive filler, there are still remaining problems in terms of the balance of viscosity increase, high thermal conductivity, and workability.

Accordingly, the problem to be solved by the present invention is to provide a thermally conductive polysiloxane composition having low viscosity, excellent workability, and high thermal conductivity, and a heat dissipation material using the same.

The inventors of the present invention focused on aluminum nitride as a thermally conductive material, and as a result of various reviews of its particle shape, particle size, and blending ratio, they finally completed the present invention.

The gist of the present invention is as follows.

(1) A thermally conductive polysiloxane composition containing (A) a thermally conductive filler, and (B) selected from the group consisting of alkoxysilyl-containing compounds and dimethylpolysiloxane One or more types, where (A) component contains two or more types of thermally conductive fillers with different average particle diameters, and contains 20% by mass or more of (A-1) average particle diameter relative to the whole (A) component Amorphous aluminum nitride particles of 30μm or more and 150μm or less.

(2) The thermally conductive polysiloxane composition as described in (1), wherein the oxygen content of the component (A-1) is less than 0.20% by mass.

(3) The thermally conductive polysiloxane composition as described in (1) or (2), wherein the aluminum nitride particles of the component (A-1) are single crystal particles.

(4) The thermally conductive polysiloxane composition according to any one of (1) to (3), wherein the component (A) contains: (A-1) component 20 to 70% by mass, (A- 2) 1 to 50% by mass of inorganic particles with an average particle diameter of 1 μm or more and less than 30 μm, and (A-3) 1 to 50% by mass of inorganic particles with an average particle diameter of 0.1 μm or more and less than 1 μm.

(5) The thermally conductive polysiloxane composition according to (4), wherein the inorganic particles of the component (A-2) are aluminum nitride particles or alumina particles.

(6) The thermally conductive polysiloxane composition as described in any one of (1) to (5), which further contains (C) polyorganosilicon containing more than one aliphatic unsaturated group in one molecule Oxane.

(7) The thermally conductive polysiloxane composition as described in any one of (1) to (6), which further contains (D) hydrogen atoms bonded to silicon atoms in one molecule having two or more hydrogen atoms Polyorganohydrosiloxane, and (E) platinum-based catalyst.

(8) The thermally conductive polysiloxane composition as described in any one of (1) to (7), wherein the component (B) is a compound containing an alkoxysilyl group, and further contains (F) condensation catalyst.

(9) A heat dissipation material composed of the thermally conductive polysiloxane composition described in any one of (1) to (8).

According to the present invention, it is possible to provide a thermally conductive polysiloxane composition with low viscosity, excellent workability and high thermal conductivity, and a heat dissipation material using the same.

The present invention is a thermally conductive polysiloxane composition containing (A) a thermally conductive filler, and (B) selected from the group consisting of alkoxysilyl-containing compounds and dimethylpolysiloxane One or more types, where (A) component contains two or more types of thermally conductive fillers with different average particle diameters, and contains 20% by mass or more of (A-1) average particle diameter relative to the whole (A) component Amorphous aluminum nitride particles of 30μm or more and 150μm or less.

[(A) Ingredient]

(A) Component is a thermally conductive filler, containing two or more types of thermally conductive fillers with different average particle diameters, and containing 20% by mass or more of (A-1) with an average particle diameter of 30μm relative to the total of (A) component Amorphous aluminum nitride particles below 150μm. Since the component (A) contains two or more thermally conductive fillers with different average particle diameters of the component (A-1), the component (A) is highly filled in the polysiloxane composition to obtain High thermal conductivity.

(A-1) Ingredients

(A-1) The component is amorphous aluminum nitride particles having an average particle diameter of 30 μm or more and 150 μm or less. (A-1) The aluminum nitride particles of the component can improve the thermal conductivity superiorly. Furthermore, compared to the case where spherical aluminum nitride particles having the same average particle diameter are used in the same content, when the component (A-1) is used, the viscosity of the thermally conductive polysiloxane composition is lower. Therefore, a thermally conductive polysiloxane composition having excellent workability and high thermal conductivity can be obtained. Furthermore, compared to the case where alumina particles having the same average particle diameter are used in the same content, when the component (A-1) is used, the thermal conductivity of the thermally conductive polysiloxane composition can be improved.

(A-1) The average particle size of the component is 30 μm or more and 150 μm or less. In addition, the component (A-1) has a particle size distribution peak in the range of 30 m or more and 150 m or less. By setting the average particle size of the component (A-1) to be 30 μm or more and 150 μm or less, even when the component (A) is highly filled in the polysiloxane composition, there is no sedimentation of the component (A-1), etc. The stability of the thermally conductive polysiloxane composition tends to increase, the viscosity decreases, and the thermal conductivity may increase. (A-1) The average particle diameter of the component is more preferably 50 μm or more and 120 μm or less, particularly preferably 60 μm or more and 100 μm or less.

In the present invention, the measured value of the average particle diameter is the median diameter (d50) measured by the laser diffraction/scattering method.

The component (A) contains 20% by mass or more of the component (A-1) with respect to the entire component (A). (A) The content rate of the component (A-1) in the component may be less than 100% by mass. More preferably, the content rate of the component (A-1) is 20% by mass or more and 70% by mass or less, still more preferably 25% by mass or more and 65% by mass or less, and particularly preferably 30% by mass or more and 60% by mass or less. (A-1) When the content of the component is less than 20% by mass, the thermal conductivity of the thermally conductive silicone composition deteriorates. Furthermore, when the content of the component (A-1) is 70% by mass or less, the workability tends to be improved.

(A-1) The oxygen content of the component is preferably less than 0.20% by mass. (A-1) When the oxygen content of the component is less than 0.20% by mass, the thermally conductive polysiloxane composition can have a lower viscosity. (A-1) The oxygen content of the component is more preferably 0.18% by mass or less, still more preferably 0.15% by mass or less, and particularly preferably 0.13% by mass or less. (A-1) Setting the oxygen content of the component to 0 is difficult to manufacture, and the lower limit of the oxygen content is, for example, 0.001% by mass. The oxygen content can be measured with EMGA-920 (manufactured by HORIBA).

The aluminum nitride particles of the component (A-1) may be single crystalline, polycrystalline, amorphous, or a mixture of these, and are preferably single crystalline particles. When the aluminum nitride particles of the component (A-1) are single crystal particles, the viscosity of the thermally conductive polysiloxane composition may become lower.

The specific surface area of the aluminum nitride particles of the component (A-1) measured by the BET method is preferably 0.01 to 0.5 m ² /g, more preferably 0.05 to 0.3 m ² /g. (A-1) When the specific surface area of the component is within this range, the viscosity of the thermally conductive polysiloxane composition may become lower.

The aluminum nitride particles of the component (A-1) can be synthesized by, for example, the so-called direct nitridation method, reductive nitridation method, or the like. In the case of aluminum nitride particles formed by the direct nitriding method, they may be further crushed to become the target particle size range. (A-1) The oxygen content of the component can be adjusted by the surface modification method in the case of aluminum nitride particles formed by the direct nitridation method. Furthermore, aluminum nitride particles of the component (A-1) are also commercially available. For example, TOYALNITE (registered trademark) TFZ-N60P, TFZ-N80P, TFZ-N100P, etc. manufactured by Toyo Aluminium Co., Ltd. can be used.

The aluminum nitride particle system of the component (A-1) may be used alone or in combination of two or more kinds.

(A-2) Ingredients and (A-3) Ingredients

In the thermally conductive polysiloxane resin composition, in order to fill the (A) thermally conductive filler more and improve the thermal conductivity, the (A) component further contains a thermal conductivity with an average particle size different from the (A-1) component The filler preferably contains (A-2) inorganic particles having an average particle diameter of 1 μm or more and less than 30 μm, and (A-3) inorganic particles having an average particle diameter of 0.1 μm or more and less than 1 μm. The inventors of the present invention have found that, compared to the case where a composition is made with a two-component system of (A-1) component and (A-3) component, in addition to (A-1) component and (A-3) component, When the component (A-2) is further added to make the composition, the difference in the particle size of each component will not be too large, and the mixing efficiency of the (A) component in the (B) component will be improved, and it is easy to obtain a uniform composition , The viscosity of the composition is also easy to become lower.

(A-2) The average particle diameter of the component is preferably 1 μm or more and less than 30 μm. In addition, the component (A-2) has a particle size distribution peak in the range of 1 μm or more and less than 30 μm. (A-2) When the average particle size of the component is 1 μm or more and less than 30 μm, the mixing efficiency when mixing the components (A-1) to (A-3) to the component (B) is more improved, and it is easy to obtain a uniform The composition, the viscosity of the composition is also easy to become lower, so it is preferred. (A-2) The average particle diameter of the component is more preferably 1 μm or more and 20 μm or less, still more preferably 2 μm or more and 15 μm or less, and particularly preferably 3 μm or more and less than 10 μm. (A-2) The average particle diameter of the component may be 1 μm or more and 10 μm or less.

(A-3) The average particle diameter of the component is preferably 0.1 μm or more and less than 1 μm. In addition, the component (A-3) has a particle size distribution peak in the range of 0.1 μm or more and less than 1 μm. (A-3) When the average particle diameter of the component is 0.1 μm or more and less than 1 μm, it is preferable in terms of thermal conductivity. (A-3) The average particle diameter of the component is more preferably 0.15 μm or more and 0.9 μm or less, particularly preferably 0.2 μm or more and 0.8 μm or less.

The blending ratio of the components (A-1) to (A-3) is preferably the component (A-1) from the viewpoint of the uniformity, low viscosity, and high thermal conductivity of the thermally conductive silicone resin composition 20 to 70 mass%, (A-2) component 1 to 50 mass%, and (A-3) 1 to 50 mass%, more preferably (A-1) component 25 to 65% by mass, (A-2) Component 5 to 45% by mass, and (A-3) 5 to 45% by mass, particularly preferably (A-1) component 30 to 60% by mass, (A-2) component 10 to 40% by mass, and (A- 3) 10 to 40% by mass.

The inorganic particles of the component (A-2) and the component (A-3) are not particularly limited as long as they are inorganic particles having thermal conductivity. As these inorganic particles, metal oxides such as aluminum oxide, zinc oxide, magnesium oxide, and silicon oxide can be used; nitrides such as aluminum nitride and boron nitride; metals such as aluminum, copper, silver, and gold; metals/ Core shell particles of metal oxides, etc.

The inorganic particles of the component (A-2) are preferably aluminum nitride particles or alumina particles in terms of uniformity, low viscosity, and high thermal conductivity of the thermally conductive polysiloxane resin composition.

The inorganic particles of the component (A-3) are preferably zinc oxide or aluminum oxide particles in terms of high thermal conductivity and improved workability.

Examples of the particle shape of the components (A-2) and (A-3) include a spherical shape, a pellet shape, an indefinite shape, a polyhedral shape, etc., but it is not limited to these shapes. (A-2) When the particle shape of the component is polyhedral, the thermal conductivity of the thermally conductive polysiloxane resin composition becomes higher, and when it is pelletized, the viscosity of the composition tends to be lower.

The components (A-2) and (A-3) may be used alone, or two or more of them may be used in combination.

In the thermally conductive polysiloxane resin composition, organic or inorganic particles other than the components (A-1) to (A-3) may be blended within a range that does not impair the effects of the present invention.

[(B) Ingredient]

(B) The component is one or more selected from the group consisting of alkoxysilyl group-containing compounds and dimethylpolysiloxane.

The alkoxysilyl group-containing compound of the component (B) preferably has at least the general formula in one molecule: -SiR ¹¹ _3-z (OR ¹² ) _z (I) represented by the alkoxysilyl group Examples of the compounds of are the compounds of the following components (B-1) to (B-5).

(In the formula, R ¹¹ is an alkyl group with 1 to 6 carbon atoms, preferably a methyl group, R ¹² is an alkyl group with 1 to 6 carbon atoms, preferably a methyl group, and z is 1, 2 or 3).

(B-1) Ingredients

Examples of the alkoxysilyl group-containing compound of the general formula (I) include compounds of the following general formula (1). Here, in the alkoxysilyl group-containing compound, ^{the unit containing R 1,} the unit containing R ^{2 and} the unit represented by SiR ³ ₂ O need not be arranged as shown in the following general formula (1), for example, It is understood that a unit represented by SiR ³ ₂ O ^{may also exist between the unit containing R 1 and} the unit containing R ^2.

(In the formula, R ¹ : a group having an alkoxysilyl group with 1 to 4 carbon atoms, R ² : a group having a siloxane unit represented by the following general formula (2) or 1 with a carbon number of 6 to 18 Valence hydrocarbon group,

(In the formula, R ^{4 is} independently a monovalent hydrocarbon group with 1 to 12 carbons, Y is a group selected from the group consisting of R ¹ , R ⁴ and aliphatic unsaturated groups, and d is an integer from 2 to 500, Preferably it is an integer from 4 to 400, more preferably an integer from 10 to 200, particularly preferably an integer from 10 to 60)

X: each independently a divalent hydrocarbon group with 2 to 10 carbons

a and b: each independently an integer of 1 or more

c: an integer above 0

a+b+c: an integer above 4

R ³ : each independently is a monovalent hydrocarbon group having 1 to 6 carbon atoms or a hydrogen atom).

As the alkoxysilyl group-containing compound of the component (B-1), it is preferable to use a compound represented by the following structural formula, but it is not limited thereto.

Further, preferred examples of the alkoxysilyl group-containing compound of the component (B-1) include compounds represented by the following structural formulas.

(B-2) Ingredients

Furthermore, as the alkoxysilyl group-containing compound of the component (B), a compound represented by the following general formula (3) can be used.

R ²¹ _e R ²² _f Si(OR ²³ ) _4-(e+f) (3)

(In the formula, R ^{21 is} independently an alkyl group with 6 to 15 carbons, R ^{22 is} independently an unsubstituted or substituted monovalent hydrocarbon group with 1 to 12 carbons (except for an alkyl group with 6 to 12 carbons), and R ^{23 is} independently It is an alkyl group having 1 to 6 carbon atoms, e is an integer of 0 to 3, preferably 1, f is an integer of 0 to 2, but e+f is an integer of 1 to 3).

Examples of R ²¹ include hexyl, octyl, nonyl, decyl, dodecyl, and tetradecyl. When ^{the carbon number of the alkyl group of R 21} is 6 to 15, the component (B) is liquid at room temperature and easy to handle, and the wettability with the component (A) is likely to become good.

Examples of R ²² include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and tertiary butyl; cycloalkyl groups such as cyclopentyl, cyclohexyl, and cyclobutyl; Aliphatic unsaturated groups such as vinyl and allyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; benzyl, 2-phenylethyl, 2-methyl-2-phenylethyl , Phenylpropyl and other aralkyl groups; groups in which part or all of the hydrogen atoms of these hydrocarbon groups are substituted by halogen atoms such as chlorine, fluorine, bromine, etc., and cyano groups, such as chloromethyl, trifluoropropyl, 3 ,3,3-Trifluoropropyl, 2-(nonafluorobutyl)ethyl, 2-(heptafluorooctyl)ethyl, chlorophenyl, bromophenyl, dibromophenyl, tetrachlorophenyl , Halogenated hydrocarbon groups such as fluorophenyl and difluorophenyl, or cyanoalkyl groups such as α-cyanoethyl, β-cyanopropyl, γ-cyanopropyl, etc., preferably methyl and ethyl.

Examples of R ²³ include methyl, ethyl, propyl, butyl, pentyl, hexyl, etc., and methyl and ethyl are preferred.

In the general formula (3), examples of the alkoxysilyl group-containing compound with e=1 include the following compounds.

C ₆ H ₁₃ Si(OCH ₃ ) ₃

C ₁₀ H ₂₁ Si(OCH ₃ ) ₃

C ₁₂ H ₂₅ Si(OCH ₃ ) ₃

C ₁₂ H ₂₅ Si(OC ₂ H ₅ ) ₃

C ₁₀ H ₂₁ Si(CH ₃ )(OCH ₃ ) ₂

C ₁₀ H ₂₁ Si(C ₆ H ₅ )(OCH ₃ ) ₂

C ₁₀ H ₂₁ Si(CH ₃ )(OC ₂ H ₅ ) ₂

C ₁₀ H ₂₁ Si(CH=CH ₂ )(OCH ₃ ) ₂

C ₁₀ H ₂₁ Si(CH ₂ CH ₂ CF ₃ )(OCH ₃ ) ₂

(B-3) Ingredients

As the alkoxysilyl group-containing compound of the component (B), dimethylpolysiloxane whose molecular chain end is chain-sealed with an alkoxysilyl group represented by the following general formula (4) can be used.

(In the formula, R ³¹ is -O- or -CH ₂ CH _{2 -.} R ^{32 is} independently an unsubstituted or substituted monovalent hydrocarbon group, specifically, the groups exemplified in R ²² of the general formula (3) Among these, alkyl and aryl are preferred, and methyl and phenyl are more preferred. R ^{33 is} independently an alkyl with 1 to 6 carbon atoms, preferably methyl, ethyl, propyl, butyl , Hexyl. g is 5 to 100, preferably 5 to 70, particularly preferably an integer of 10 to 50, p is an integer of 1 to 3, preferably 2 or 3).

One or more of the methyl groups of the general formula (4) may be substituted with a monovalent hydrocarbon group other than the methyl group. Examples of the substituent include alkyl groups such as ethyl, propyl, hexyl, and octyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; aryl groups such as phenyl and tolyl; 2-phenylethyl, 2 -Methyl-2-phenylethyl and other aralkyl groups; 3,3,3-trifluoropropyl, 2-(nonafluorobutyl)ethyl, 2-(heptafluorooctyl)ethyl, p- -Halogenated hydrocarbon groups, such as chlorophenyl groups, having 1 to 10 carbon atoms.

(B-4) Ingredients

As the alkoxysilyl group-containing compound of the component (B), a compound in which both ends of the molecular chain represented by the following general formula (5) are sealed with an alkoxysilyl group can be used.

(In the formula, R ³⁴ , R ³⁵ , R ³⁶ and q are independent and ^{synonymous with R 31} , R ³² , R ³³ and p in general formula (4), and h is the viscosity at 23°C from 10 to 10,000 mPa‧s, more preferably an integer from 20 to 5,000mPa‧s).

One or more of the methyl groups of the general formula (5) may be substituted with a monovalent hydrocarbon group other than the methyl group. As the substituent, the substituent exemplified as the substitutable methyl group in the general formula (4) can be exemplified

Examples of the alkoxysilyl-containing compound represented by the general formula (5) include methyl dimethoxy dimethyl polysiloxane at both ends and trimethoxy dimethyl polysiloxane at both ends. .

(B-5) Ingredients

As the dimethylpolysiloxane of the component (B), a linear compound represented by the following general formula (6) can be used.

(In the formula, i is an integer ranging from 10 to 10,000mPa‧s for the viscosity at 23°C, more preferably from 20 to 5,000mPa‧s).

One or more of the methyl groups of the general formula (6) may be substituted with a monovalent hydrocarbon group other than the methyl group. As a substituent, the substituent exemplified as a group which can replace a methyl group in the general formula (4) can be exemplified.

As the component (B), the component (B-1) is preferred from the viewpoint of improvement in workability.

With respect to 100 parts by mass of (A) component, the content of (B) component in the thermally conductive polysiloxane composition is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, and particularly preferably 1 to 10 parts by mass share.

(B) A component may be independent or may use 2 or more types together.

[Other ingredients]

The thermally conductive polysiloxane composition may contain components other than the (A) component and the (B) component in accordance with the purpose and method of use of the composition.

[(C) Ingredient]

As the polyorganosiloxane containing one or more aliphatic unsaturated groups in one molecule of the component (C), one represented by the following average composition formula (II) can be used.

R ⁴¹ _j R ⁴² _k SiO _[4-(j+k)]/2 (II)

(In the formula, R ⁴¹ is an aliphatic unsaturated group, and R ⁴² is a substituted or unsubstituted monovalent hydrocarbon group that does not contain an aliphatic unsaturated bond. j and k satisfy 0<j<3, 0<k<3, 1<j+k<3 positive number).

The aliphatic unsaturated group in R ⁴¹ preferably has a carbon number in the range of 2 to 8, and examples thereof include vinyl, allyl, propenyl, 1-butenyl, 1-hexenyl, etc., preferably For vinyl. The aliphatic unsaturated group contains one or more in one molecule, preferably two or more. Furthermore, the aliphatic unsaturated group can also be bonded to the silicon atom at the end of the molecular chain, the silicon atom in the middle of the molecular chain, or both.

Specific examples of R ^{42 include the groups exemplified in R 22 of} the general formula (3), but do not contain aliphatic unsaturated groups such as vinyl groups and allyl groups. Among these, alkyl and aryl are preferred, and methyl and phenyl are more preferred.

j, k preferably satisfy 0.0005≦j≦1, 1.5≦k<2.4, 1.5<j+k<2.5, and more preferably satisfy 0.001≦j≦0.5, 1.8≦k≦2.1, 1.8<j+k≦2.2 The number.

The molecular structure of the component (C) can be linear, branched, or cyclic, preferably linear or branched.

The viscosity of the component (C) at 23°C is preferably 10 to 10,000 mPa‧s. More preferably, it is 20 to 5,000mPa‧s.

When the composition contains (C) component, the total amount of (B) component and (C) component is 1.5 to 35 parts by mass, preferably 1.5 to 30 parts by mass relative to 100 parts by mass of (A) component , More preferably 1.5 to 28 parts by mass. (B) component and (C) component are such that the content ratio of (C) component in the total amount of (B) component and (C) component is 15 to 98% by mass, preferably 18 to 98% by mass, and more It is better to mix it in the range of 20 to 98% by mass.

The component (C) may be used alone or in combination of two or more kinds.

[(D) Ingredient]

The component (D) is a polyorganohydrosiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule, and the component (C) and component (B) have at least one aliphatic unsaturated group Compounds containing alkoxysilyl groups (for example, ^{Y in R 2} of general formula (1), R ²² of general formula (3), R ^{32 of general formula (4), or R 35 of} general formula (5) In the case of a compound belonging to an aliphatic unsaturated group), it becomes a component of the crosslinking agent of the component (B). (D) The component has two or more hydrogen atoms bonded to silicon atoms in one molecule, and preferably has three or more hydrogen atoms. This hydrogen atom can be bonded to the silicon atom at the end of the molecular chain, it can also be bonded to the silicon atom in the middle of the molecular chain, or it can be bonded to both. In addition, polyorganohydrosiloxanes having hydrogen atoms bonded only to silicon atoms at both ends can also be used. (D) The molecular structure of the component may be linear, branched, cyclic, or three-dimensional mesh. It may be singly or in combination of two or more.

As the component (D), those represented by the following average composition formula (III) can be used.

R ⁵¹ _m H _n SiO _[4-(m+n)]/2 (III)

(In the formula, R ⁵¹ is a substituted or unsubstituted monovalent hydrocarbon group that does not have an aliphatic unsaturated bond. m and n are numbers satisfying 0.5≦m≦2, 0<n≦2, 0.5<m+n≦3 ).

Specific examples of R ^{51 include the groups exemplified in R 22 of} the general formula (3), but do not include aliphatic unsaturated groups such as vinyl groups and allyl groups. Among these, in terms of ease of synthesis and cost, an alkyl group is preferred, and a methyl group is more preferred.

m and n are preferably numbers satisfying 0.6≦m≦1.9, 0.01≦n≦1.0, and 0.6≦m+n≦2.8.

The viscosity of component (D) at 23°C is preferably 10 to 500 mPa‧s.

(D) The compounding amount of the component, when the (C) component and (B) component belong to the alkoxysilyl group-containing compound having at least one aliphatic unsaturated group, relative to the bond to (B) One aliphatic unsaturated group of the silicon atom of the component (D) is 0.1 to 1.5, preferably 0.2 to 1.2 of the hydrogen atoms bonded to the silicon atom in the component (D). (D) When the blending amount of the component is within the above range, the thermally conductive polysiloxane composition has good stability over time, the degree of crosslinking after curing is likely to be sufficient, and it is easy to obtain a cured product with appropriate hardness.

[(E) Ingredient]

The component (E) is a platinum-based catalyst, and when the component (C) and the component (B) are alkoxysilyl-containing compounds having at least one aliphatic unsaturated group, the component (B), After mixing with component (D), component (E) is a component that promotes hardening. As the (E) component, a well-known catalyst used in the hydrosilyl reaction can be used. For example, platinum black, platinum(II) chloride, chloroplatinic acid, the reactant of chloroplatinic acid and monohydric alcohol, the complex of chloroplatinic acid and olefins or vinylsiloxane, platinum-vinyl tetramer Complexes, platinum diacetyl acetate, etc. (E) The compounding amount of the component can be adjusted appropriately according to the desired curing speed, etc. The components (C) and (B) are alkoxy-containing silyl groups having at least one aliphatic unsaturated group In the case of the compound, the total amount of (B) component and (D) component is preferably in the range of 0.1 to 1,000 ppm in terms of platinum element. (E) The component may be used alone, or two or more of them may be used in combination.

Furthermore, in order to obtain a longer service life, the activity of the catalyst can be suppressed by the addition of (E-2) reaction inhibitor. Examples of known reaction inhibitors for platinum group metals include acetylene alcohols such as 2-methyl-3-butyn-2-ol and 1-acetylene-2-cyclohexanol.

[(F) Ingredient]

The component (F) is a condensation catalyst, and when the component (B) is a compound containing an alkoxysilyl group, it is a component that promotes the condensation and hardening of the component (B). As (F) component, a well-known silanol condensation catalyst can be used. Examples include titanium-based esters such as tetrabutyl titanate and tetrapropyl titanate; organotin compounds such as dibutyl tin dilaurate, dibutyl tin maleate, and dibutyl tin diacetate; tin octylate , Tin naphthenate, tin laurate, tin neodecanoate and other tin carboxylates; reactant of dibutyl tin oxide and phthalate; dibutyl tin acetone; aluminum triacetone, triethyl Organic aluminum compounds such as aluminum acetyl acetate, aluminum diisopropoxy ethyl acetyl acetate; diisopropoxy-bis(ethyl acetyl acetate) titanium, zirconium tetraacetylacetone, titanium tetraacetylacetone, etc. Chelating compounds; lead octoate; iron naphthenate; bismuth-tris (neodecanoate), bismuth-tris (2-ethylhexanoate) and other metal-based catalysts. Furthermore, well-known amine catalysts, such as lauryl amine, can also be used. Among these, particularly preferred are carboxylate tin salts such as dibutyl tin dilaurate, dibutyl tin maleate, dibutyl tin diacetate, tin octoate, tin naphthenate, tin laurate, tin neodecanoate, etc. Organotin compounds; reactants of dibutyltin oxide and phthalate; tin catalysts such as dibutyltin diacetone acetone.

The compounding amount of the component (F) can be adjusted appropriately according to the desired curing speed, etc., relative to 100 parts by mass of the alkoxysilyl group-containing compound in the component (B), it is adjusted to 0.01 to 10 parts by mass, Preferably it is 0.05 to 8.0 parts by mass, more preferably 0.1 to 5.0 parts by mass.

The component (F) may be used alone or in combination of two or more kinds.

[(G) Ingredient]

The thermally conductive polysiloxane composition system can further meet the needs and may contain flame retardant imparting agents, heat resistance enhancers, plasticizers, colorants, adhesive imparting materials, and diluents within the scope of not impairing the purpose of the present invention. Wait.

[Preferable composition aspect]

The thermally conductive polysiloxane composition system contains the above-mentioned other components in addition to the (A) component and (B) component, and can be in the form of the following 1 to 3 preferred compositions.

1. Grease-type thermally conductive polysiloxane composition

The thermally conductive polysiloxane composition system may include only the (A) component and the (B) component, or the (C) component may be added to form a grease-type thermally conductive polysiloxane composition. This embodiment does not harden the thermally conductive polysiloxane composition and can be directly used as a heat dissipation material. The grease-type thermally conductive polysiloxane composition may further contain one or more of the group consisting of the components (D) to (G), and preferably does not contain the components (D) to (F).

2. Addition reaction type thermally conductive polysiloxane composition

The thermally conductive polysiloxane composition is composed of components (A) and (B) which are alkoxysilyl-containing compounds having at least one aliphatic unsaturated group (for example, in R ² of the general formula (1) In the case of Y, R ²² of general formula (3), R ^{32 of general formula (4) or R 35 of} general formula (5) belonging to aliphatic unsaturated group), in addition to the component (B), it may contain (D) component and (E) component. In addition, the thermally conductive polysiloxane composition may contain (C), (D), and (E) components in addition to (A) components and (B) components. In this embodiment, the thermally conductive polysiloxane composition can be hardened by the addition reaction, from the point that it can become a heat dissipating material composed of the hardened material of the thermally conductive polysiloxane composition. It is better. In the latter case, the component (B) may or may not have an aliphatic unsaturated group. The addition reaction type thermally conductive polysiloxane composition may further have one or more of the group consisting of the (F) component and the (G) component.

3. Condensation reaction type thermally conductive polysiloxane composition

The thermally conductive polysiloxane composition contains the (B) component as an alkoxysilyl group-containing compound, and may further contain the (F) component in addition to the (A) component and (B) component. This embodiment can be hardened by subjecting the thermally conductive polysiloxane composition to a condensation reaction, and it is preferable from the point that it can be a heat-dissipating material composed of a hardened material of the thermally conductive polysiloxane composition. The condensation reaction type thermally conductive polysiloxane composition may further contain one or more of the group consisting of (C), (D), (E), and (G) components.

In the aspect of the condensation reaction type thermally conductive polysiloxane composition, the component (B) contains at least an alkoxysilyl group-containing compound. As the alkoxysilyl group-containing compound of component (B), dimethylpolysiloxane containing dialkoxysilyl groups or trialkoxysilyl groups at both ends of the molecular chain or at the ends of the molecular chain pieces is preferred alkyl. Particularly preferred is dimethylpolysiloxane containing dialkoxysilyl or trialkoxysilyl at both ends of the molecular chain.

[Manufacturing method of thermally conductive polysiloxane composition]

The thermally conductive polysiloxane composition system can be obtained by mixing (A) component and (B) component, as well as other optional components as required, with a mixer such as a planetary mixer. When mixing, it can be mixed while heating in the range of 50 to 150°C as required. For more uniform completion, it is preferable to perform the kneading operation under high shearing force. As the kneading device, there are a three-roll grinder, a colloid mill, a sand mill, etc., and among them, a method using a three-roll grinder is preferred.

[The curing method of thermally conductive polysiloxane composition]

As a method of curing the addition reaction type thermally conductive polysiloxane composition, for example, a method of placing the composition at room temperature after applying the composition to a substrate that requires exothermic heat, or using 50% Method of heating to 200℃. From the viewpoint of rapidly hardening the composition, it is preferable to adopt a method of heating.

As a method of curing the condensation reaction type thermally conductive polysiloxane composition, for example, after coating the composition with a substrate that needs to release heat, the composition is placed at room temperature, and the composition is exposed to moisture in the air. The method of curing by air, or the method of curing under humidified conditions.

[Heat Dissipation Material]

A heat-dissipating material composed of a thermally conductive polysiloxane composition or a thermally conductive polysiloxane composition has a thermal conductivity of 2.0W/(m‧K) or more at 23℃ as measured by the hot wire method, preferably 2.5W/(m‧K) or more, more preferably 3.0W/(m‧K) or more. In order to adjust the thermal conductivity and increase the heat radiation effect, the content of the component (A) in the composition is preferably 80% by mass or more, and the content of the component (A) can be increased in accordance with the required thermal conductivity.

Heat dissipation materials are used in addition to PCs/servers equipped with CPUs that generate a lot of heat, power modules, ultra-LSIs, electronic devices equipped with optical components (optical reading heads, LEDs), and home appliances (DVD/HDD recorders) (Player), FPD and other AV equipment, etc.), PC peripheral equipment, home game consoles, other than automobiles, inverters, switching power supplies and other industrial equipment such as heat dissipation materials. The heat-dissipating material may have the form of grease (paste), gel, rubber, or the like.

[Example] <Ingredients used> (A-1) Ingredients

AlN-1: Unshaped aluminum nitride particles (single crystal particles), average particle size 60μm, oxygen content 0.21% by mass

AlN-2: Amorphous aluminum nitride particles (single crystal particles) treated with AlN-1 by the surface modification method, with an average particle size of 60μm and an oxygen content of 0.10% by mass

AlN-3: Amorphous aluminum nitride particles (single crystal particles, average particle size 80μm) treated by surface modification method, average particle size 80μm, oxygen content 0.09% by mass

AlN-4: Amorphous aluminum nitride particles (single crystal particles, average particle size 100μm) treated by surface modification method, average particle size 100μm, oxygen content 0.08% by mass

(A’) Component: Other thermal conductive fillers

Spherical aluminum nitride particles (granulated particles), with an average particle size of 80μm

Spherical aluminum nitride particles (granulated particles), with an average particle size of 50μm

Spherical alumina particles with an average particle size of 75μm

(A-2) Ingredients

Spherical aluminum nitride particles with an average particle size of 5μm

Al ₂ O ₃ -2: Pellets of alumina particles, with an average particle size of 3.3μm

Al ₂ O ₃ -1: Polyhedral alumina particles with an average particle size of 4.7μm

Unshaped alumina particles with an average particle size of 18μm

(A-3) Ingredients

Pellets of alumina particles with an average particle size of 0.5μm

(B-1) Ingredients

Polyorganosiloxanes containing trialkoxy groups:

(B-2) Ingredients

Methyltrimethoxysilane

(B-4) Ingredients

Both ends of methyl dimethoxy dimethyl polysiloxane (viscosity: 100mPa‧s)

(B-5) Ingredients

Trimethylsilyl dimethyl polysiloxane at both ends (Viscosity: 30mPa‧s)

(C) Ingredients

Vinyl dimethyl polysiloxane at both ends (viscosity: 30mPa‧s)

(D) Ingredients

Polyorganohydrogensiloxane: H oil (M ^H D ^H ₈ D ₈ M ^H )

(E) Ingredients

Platinum-based catalyst: 2% platinum content vinyl tetramer complex

(E-2) Ingredients

Reaction inhibitor: 1-acetylene-1-cyclohexanol

(F) Ingredients

Condensation catalyst: diisopropoxy-bis(ethyl acetyl acetate) titanium

<Measurement method> [The average particle size]

The average particle size (median diameter d50) is measured by the laser diffraction/scattering method.

[Viscosity]

According to JIS K6249. The viscosity of the composition at 23°C was measured with a rotary viscometer rotor No. 7 at a rotation speed of 2 rpm and a value of 5 minutes.

[Thermal conductivity]

The measurement was performed at 23° C. in accordance with the Hot disk method using a Hot disk method thermophysical property measuring device (manufactured by Kyoto Electronics Industry Co., Ltd., TPS 1500).

Examples 1 to 12 and Comparative Examples 1 to 6 (addition reaction type thermally conductive polysiloxane composition)

The components (A), (B) and (C) shown in Tables 1 and 2 were fed into a planetary mixer (manufactured by DULTON), stirred and mixed at room temperature for 1 hour, and further stirred and mixed at 120°C for 1 hour. After the mixture was cooled, it was cooled to 25°C. After that, the components (D), (E), and (E-2) are added and mixed to the aforementioned mixture to obtain an addition reaction type thermally conductive polysiloxane composition. The viscosity of the composition thus obtained was measured. The results are shown in Tables 1 and 2.

For the addition reaction type thermally conductive polysiloxane compositions of Examples 1 to 12 and Comparative Examples 1 to 6, the addition reaction type thermal conductivity of 6mm in thickness was obtained by heating and curing in a mold at 150°C for 1 hour It is a hardened material of a polysiloxane composition. The thermal conductivity of the cured product thus obtained was measured. The results are shown in Tables 1 and 2.

By comparing Example 4 with Comparative Example 1, it can be seen that compared to Comparative Example 1 in which spherical aluminum nitride particles with the same particle size are used in the same content instead of (A-1) component, it belongs to the conductive filling of (A) component The agent contains two or more types of thermally conductive fillers with different average particle diameters, and contains 20% by mass or more of (A-1) amorphous nitride with an average particle diameter of 30μm or more and 150μm or less with respect to the whole component (A). The composition of Example 4 of the aluminum particles has a low viscosity. In addition, it can also be seen that the composition system of Example 4 has high thermal conductivity compared to Comparative Example 3 in which spherical alumina particles having almost the same particle diameter are used in place of the component (A-1) at the same content.

By comparing Examples 1, 2 and 8, Comparative Examples 4 to 7, and Comparative Examples 3, 9 and 10, respectively, it can be seen that amorphous aluminum nitride particles with an average particle diameter of 80 μm are used as the component (A-1) In this case, high thermal conductivity can be achieved, so it is particularly good.

By comparing Examples 1 and 8, Comparative Examples 5 and 7, Comparative Examples 9 and 10, and Comparative Examples 11 and 12, respectively, it can be seen that the oxygen content belonging to the component (A-1) is less than 0.20% by mass The examples 8, 7, 9 and 11 of the series have lower viscosity, so they are particularly good.

By comparing Examples 1, 5 and 10, Comparative Examples 2 to 4, and Comparative Examples 7 to 9, it can be seen that even if the component (A-2) is either aluminum nitride particles or alumina particles, It can have both low viscosity and high thermal conductivity. The composition of (A-2) component has little influence on these characteristics.

By comparing Examples 5 and 10, and Comparative Examples 7 and 9, it can be seen that the composition of Examples 10 and 9 in which the component (A-2) is polyhedral alumina particles is excellent in thermal conductivity, and pellet oxidation is used. The compositions of Examples 5 and 7 of aluminum particles have lower viscosity.

By comparing Examples 7 and 11, and Comparative Examples 5 and 12, respectively, it can be seen that the compositions of Examples 11 and 12, which have an increased filling rate of the thermally conductive filler belonging to the component (A), have better compositions than those of Examples 7 and 5. The composition has higher thermal conductivity.

The thermoconductive polysiloxane composition in Table 2 further improves the thermal conductivity, and the content ratio of component (A) is increased to 94.4%. In Examples 11 and 12 that used amorphous aluminum nitride particles with an average particle diameter of 60 μm as the component (A-1), it can be seen that the viscosity was increased by increasing the content ratio of the component (A) compared to Examples 1 to 10. However, compared with Comparative Examples 5 and 6 in which the component (A-1) was replaced with spherical aluminum nitride particles having an average particle diameter of 80 μm and 50 μm, respectively, the viscosity of Examples 11 and 12 was lower. From this result, it can also be seen that the content of the (A-1) component with respect to the entire (A) component is 20% by mass or more to effectively reduce the viscosity of the thermally conductive polysiloxane composition.

Example 13 (Condensation reaction type thermally conductive polysiloxane composition)

The components (A) and (B) shown in Table 3 were fed into a planetary mixer (manufactured by DULTON), stirred and mixed at room temperature for 1 hour, and further stirred and mixed at 120°C for 1 hour to obtain a mixture, and then cooled to 25 ℃. After that, the component (F) is added to the aforementioned mixture and mixed to obtain a condensation reaction type thermally conductive polysiloxane composition. The viscosity of the composition thus obtained was measured. The results are shown in Table 3.

Regarding the condensation reaction type thermally conductive polysiloxane composition of Example 13, it was filled in a mold with a thickness of 6 mm without being covered and left at 23°C and 50% RH for 14 days to obtain a condensation reaction type thermally conductive polysiloxane. The hardened substance of the composition. The thermal conductivity of the cured product thus obtained was measured. The results are shown in Table 3.

As in Example 13, the thermally conductive filler belonging to component (A) contains two or more thermally conductive fillers with different average particle diameters, and (A-1) amorphous aluminum nitride with an average particle diameter of 30μm or more and 150μm or less The particles contain at least 20% by mass relative to the total component (A). Furthermore, component (B) is a compound containing alkoxysilyl groups. When the composition contains a condensation catalyst (F), it has a low viscosity and heat conduction. Condensation reaction type thermally conductive polysiloxane composition with high performance.

Example 14 (grease-type thermally conductive polysiloxane composition)

The components (A) and (B) shown in Table 4 were fed into a planetary mixer (manufactured by DULTON), stirred and mixed at room temperature for 1 hour, and further stirred and mixed at 120°C for 1 hour to obtain a mixture, and then cooled to 25 °C to obtain a grease-type thermally conductive polysiloxane composition. The viscosity of the composition thus obtained was measured. The results are shown in Table 4.

Regarding the grease-type thermally conductive polysiloxane composition of Example 14, the thermal conductivity of a thickness of 6 mm was measured. The results are shown in Table 4.

As in Example 14, the (A) component thermally conductive filler contains two or more thermally conductive fillers with different average particle diameters, and (A-1) Amorphous aluminum nitride particles with an average particle diameter of 30μm or more and 150μm or less When it contains 20% by mass or more with respect to the entire component (A), and contains one or more of the group consisting of (B) alkoxysilyl group-containing compound and dimethylpolysiloxane, it can have a low viscosity. In addition, a grease-type thermally conductive polysiloxane composition with high thermal conductivity.

[Industrial availability]

The thermally conductive polysiloxane composition of the present invention can be used as a heat-dissipating material for various devices with heat-generating parts such as personal computers and other electronic devices.

Claims (8)

A thermally conductive polysiloxane composition containing (A) a thermally conductive filler, and (B) one selected from the group consisting of alkoxysilyl-containing compounds and dimethylpolysiloxane Among the above, with respect to the entire component (A), component (A) contains: (A-1) amorphous aluminum nitride particles with an average particle size of 30 μm or more and 150 μm or less, 20 to 70% by mass, and (A-2) average particle size 1 to 50% by mass of inorganic particles with a diameter of 1 μm or more and less than 30 μm, and (A-3) inorganic particles with an average particle size of 0.1 μm or more and less than 1 μm, but the inorganic particles of the component (A-2) exclude metal aluminum powder. The thermally conductive polysiloxane composition described in item 1 of the scope of patent application, wherein the oxygen content of the component (A-1) is less than 0.20% by mass. The thermally conductive polysiloxane composition described in item 1 or 2 of the scope of patent application, wherein the aluminum nitride particles of the component (A-1) are single crystal particles. The thermally conductive polysiloxane composition described in the first item of the scope of patent application, wherein the inorganic particles of the component (A-2) are aluminum nitride particles or alumina particles. The thermally conductive polysiloxane composition described in item 1 or 2 of the scope of the patent application further contains (C) a polyorganosiloxane containing more than one aliphatic unsaturated group in one molecule. The thermally conductive polysiloxane composition as described in item 1 or 2 of the scope of patent application, which further contains (D) a polyorganohydrogensiloxane having two or more hydrogen atoms bonded to silicon atoms in one molecule , And (E) platinum-based catalyst. The thermally conductive polysiloxane composition described in item 1 or 2 of the scope of the patent application, wherein the component (B) is a compound containing an alkoxysilyl group, It also contains (F) condensation catalyst. A heat-dissipating material consisting of the thermally conductive polysiloxane composition described in any one of items 1 to 7 of the scope of patent application.